Typical automotive strut suspension systems include a damper tube connected to the unsprung mass of the vehicle, a piston rod slidable on the damper tube and connected to the sprung mass of the vehicle, and a spring around the strut reacting against a seat on the damper tube and against a seat on the sprung mass. The spring may be a coil spring or an air spring of the type having a reinforced flexible sleeve sealed at the bottom on an air spring piston on the damper tube and at the top on an end retainer on the sprung mass. To minimize side loads on the rod and on the piston, the springs in some strut suspension systems are tilted relative to the struts so that the spring resultant forces more closely approach a theoretical optimum inclination. An air spring end retainer according to this invention contributes to optimization of the angle of inclination of an air spring in a strut suspension system.